Study Guide
Geology 303, SDSU Spring
PEOPLE for TEST 1:
1) Alfred Wegener: the most famous and outspoken proponent of continental
drift. German meteorologist. Put evidence together that supported the idea
that all the continents were unified into a single landmass and called it
Pangaea (all-earth).
2) Steno (Niels Steensen): Danish physician who developed several laws that are
fundamental in interpreting geologic history. These include the laws of original
continuity and superposition.
NATURAL DISASTER CASE HISTORIES for TEST 1:
1) Lisbon earthquakes (Chapter 3);
2) Lituya Bay, Alaska, 1958 (Chapter 8);
3) Tsunami of 2004, Indian Ocean (Chapter 8);
4) Krakatoa eruption of 1883 (Chapter 8);
5) Crescent City, California, tsunami during 1964 (from 1964 Good Friday
Earthquake in Alaska-Chapter 8);
6) The great 1700 earthquake along the Cascadia Subduction Zone (Pacific
Northwest-Chapter 4);
7) Mexico City earthquake of 1985 (Chapter 4);
GEOLOGY TERMS/CONCEPTS for TEST 1:
1.(2)-asthenosphere: The layer of the Earth below the lithosphere in which
isostatic adjustments take place; the asthenosphere is about 200 km thick. The
rocks here deform readily and flow slowly (see ductile or plastic behavior).
2.(2)-uniformitarianism/actualism: Uniformitarianism (“The present is the key to
the past”) is the concept that the same laws and processes operating on and
within the Earth throughout geologic time are the same laws and processes
operating today. Actualism is using the actual processes operating on Earth
today to interpret the past; not inventing unrecognized processes to explain the
past.
3.(2)-convergence zone: A linear area where plates collide and move closer
together. This is a zone earthquakes, volcanoes, mountain ranges and deep
ocean trenches.
4.(2)-core: The central zone or nucleus of Earth about 2,900 km (1,800 miles)
below the surface. The core is made mostly of iron and nickel and exists as a
solid inner zone (2450 km in diameter with temperatures up to 4300 degrees C or
7770 degrees F; similar in temperature to the surface of the Sun) surrounded by a
liquid outer shell. The Earth’s magnetic field originates within the liquid core,
where viscous movements of convections currents in the outer core generates
the magnetic field.
5.(2)-crust: The outermost layer of the lithosphere, composed of relatively lowdensity materials. The continental crust (granitic) has lower density than the
oceanic crust (basaltic).
6.(2)-divergence zone: A linear zone formed where plates pull apart, as at a
spreading center (ridge).
7.(2)-ductile: Behavior of material whereby stress causes permanent flow or
strain. Ductility is the ability to change shape markedly without breaking
(fracture): “plastic” behavior.
8.(2)-elastic: Behavior of material whereby stress causes deformation that is
recoverable; when stress stops, the material returns to its original state (if stress
greater than the yield strength of brittle material it can fracture). Pulling on a
rubber band is an example where if you let go before it snaps, it returns to its
original state.
9.(2)-epicenter: The point on the surface of the Earth directly above a fault
movement (i.e., earthquake location).
10.(2)-hot-spot: A place on Earth where a plume of magma has risen upward from
the mantle (i.e., a mantle plume!) and through a plate to reach the surface. This
happens, for example, at the Hawaiian and Galapagos Islands and creates a chain
of islands with the islands becoming progressively older away from the hot spot.
This is evidence of plate motion and can determine plate velocity and direction
over hot spot.
11.(2)-igneous rock: Rock formed by the solidification (crystallization) of magma
or lava. Granite and basalt are igneous rock; granite=continental crust, plutonic
rock from magma, less dense than basalt; basalt=oceanic curst, volcanic rock
from lava, more dense than granite (so oceanic lithosphere subducts and is
recycled).
12(2)-lithosphere: The outer rigid shell of the Earth that lies above the
asthenosphere and below the atmosphere and hydrosphere. The lithosphere is
comprised of the crust (oceanic and continental) and the upper, rigid mantle.
13.(2)-mantle: The largest zone of the Earth, comprising 83% by volume and 67%
by mass.
14.(2)-oldest rock and mineral: The oldest mineral is a zircon (sand grain) dated
at 4.37 billion years old from a sandstone in western Australia; the oldest rock is
dated at 4.055 billion years old from northwest Canada. Compare this to the
oldest seafloor rock that is 200 million years old (remember the seafloor is
continually recycled). The age of the Earth has to be older than the oldest rocks
and minerals, and is about 4.6 billion (4,600 million) years old.
15.(2)-Pangaea: A supercontinent that existed during Late Paleozoic time when all
the continents were unified into a single landmass.
16.(2)-plume: An arm of magma rising upward from the mantle. Not necessarily
liquid, can be solid rock.
17.(2)-radioactivity: The breakdown of unstable atomic nuclei by emission of
particles or radiation and energy is released. Source of energy keeping Earth’s
interior hot. The early Earth was transformed by this heat along with impact and
gravitational energy.
18.(2)-ridge: A volcanic mountain range that lies along the spreading centers on
the floors of the oceans.
19.(2)-seafloor spreading: Where tectonic plates pull apart, magma wells up and
solidifies to create volcanic mountains, which in turn are pulled apart as new
ocean floor.
20.(2)-strain and stress: Stress: external forces acting on masses or along
surfaces; forces include shear, tension and compression. Strain: A change in the
form or size of a body due to external forces.
21.(2)-subduction and trench: The process of lithospheric plate descending
beneath another one. Trenches mark the downgoing edges of subducting plates
and are narrow and elongate troughs where ocean water can be more than twice
its normal depth. The older, colder OCEANIC (only oceanic lithosphere subducts)
plate subducts beneath either a continental plate or younger, warmer oceanic
plate. For example, check out where the Pacific plate is created and destroyed
(where are the ridges and trenches? Transforms?).
22.(2)-plate tectonics and tectonic cycle: New lithosphere forms at oceanic
volcanic ridges, the lithospheric plates (a piece of the lithosphere that move a top
the asthenosphere; there are a dozen large plates and many smaller ones) spread
apart to open ocean basins, and then the oceanic plates are reabsorbed into the
mantle at subduction zones (marked by trenches at Earth’s surface). Plate
tectonics is the description of the movements of plates and the effects of plate
formation (at ridges), collision (at convergent zones), subduction (at convergent
zones) and slide past (at transform or strike-slip zones). The typical time for a
complete plate-tectonic cycle is in excess of 250 million years.
23.(2)-transform fault: A strike-slip fault that connects the ends of two offset
segments of plate edges, such as spreading centers or subduction zones. The
San Andreas Fault is a transform plate boundary and a right-lateral, strike slip
fault. Most movement is horizontal displacement of the Earth’s crust.
24.(3)-amplitude: The maximum displacement or height of a wave crest or depth
of a trough.
25.(3)-body wave: Seismic wave that travels through the body of the Earth-for
example, P and S-waves.
26.(3)-cross section: A two-dimensional drawing showing features in the vertical
plane, as in a canyon wall, road cut or mine.
27.(3)-dip: The angle of inclination measured in degrees from the horizontal.
28.(3)-dip-slip fault: Fault where most of the movement is either up or down
(vertical) in response to pushing or pulling.
29.(3)-fault: A fracture or belt of fractures in rock where two sides move past each
other. The most common cause of earthquakes is sudden movements along
faults.
30.(3)-footwall: The underlying side or block of a fault. (rock that lies beneath the
fault plane).
31.(3)-hangingwall: The overlying side or block of a fault (rock that lies above the
fault plane).
32.(3)-hypocenter (focus) and epicenter: The initial portion of a fault that moved
to generate an earthquake. Hypocenters are below the ground surface;
epicenters are above them and on the Earth’s surface.
33.(3)-law of original horizontality: Sediments are deposited in nearly horizontal
layers.
34.(3)-law of superposition: In a sequence of sedimentary rock layers, the oldest
layer is at the base, and ages are progressively younger toward the top.
35.(3)-magnitude: An assessment of the size of an event. Magnitude scales exist
for earthquakes, volcanic eruptions, hurricanes and tornadoes. For earthquakes,
magnitudes are calculated based on the energy released and are used to
compare earthquakes. The largest earthquake ever recorded by a seismograph
occurred during 1960 in Chile (9.5 magnitude).
36.(3)-mainshock: The largest earthquake in a sequence, preceded by foreshocks
and followed by aftershocks.
37.(3)-normal fault: A dip-slip fault in which the upper fault block (hanging wall)
has moved downward in response to tensional (pull-apart) stresses.
38.(3)-P (primary)-wave: The first seismic wave (body wave) to reach a
seismometer. Movement is by alternating push-pull pulses that travel through
solid, liquid and gas.
39.(3)-reverse fault: A dip-slip fault where the upper fault block (hanging wall) has
moved upward in response to compressional stresses.
40.(3)-right-lateral fault: A strike-slip fault where most of the displacement is
toward the right hand of a person straddling the fault. The San Andreas is a rightlateral strike slip fault (AND a transform plate boundary).
41.(3)-S(secondary)-wave: Second seismic wave (body wave) to arrive at the
seismometer. Movement occurs by shearing particles at right angles to the
travel path. S-waves move through solids only, and stop at the core/mantle
boundary! Why? Think about it.
42.(3)-strike: The compass bearing of the trend of a rock layer as viewed in the
horizontal plane.
43.(3)-strike-slip fault: Fault in which most of the movement is horizontal or slidepast in character. The San Andreas Fault in California is a transform plate
boundary between the Pacific and North American Plates AND it is also a rightlateral, strike slip fault, more than 800 miles long!
44.(3)-surface wave: A class of seismic waves that travel along the surface onlyfor example, Love and Rayleigh waves. These create most of the destruction
during seisms. These waves travel the slowest through rock.
45.(3)-wavelength: The distance between two successive peaks, or troughs, in
seismic waves or ocean waves.
46.(4)-liquefaction: The temporary transformation of water-saturated, loose
sediment into a fluid; typically caused by seismic waves. Example occurred in
the Marina District during the World Series earthquake of 1989.
47.(4)-rift: The valley created at a pull-apart zone. Term commonly describes the
valley that occurs along the axis of the volcanic mountain ranges where seafloor
spreading occurs. Make sure to read and understand the geologic processes
happening where we live; rifting of continental crust and development of a
spreading center that opened the Gulf of California beginning about 5.5 million
years ago-Baja torn from North American plate and piggybacked onto the Pacific
plate; read Chapter 4 beginning on page 82 and bottom of page 95 for more.
48.(4)-seismic-gap method: Earthquakes are expected next along those fault
segments that have not moved for the longest time.
49.(8)-fetch: The length of water surface the wind blows across to create waves or
lake-effect snow.
50.(8)-rogue wave: An unusually tall wave created when several wave systems
briefly and locally combine their energies.
51.(8)-seiche: An oscillating wave on a lake or landlocked sea that varies in
period from a few minutes to several hours. Pronounced saysh.
TEST 1
PEOPLE FOR TEST 2: TBD
NATURAL DISASTER CASE HISTORIES FOR TEST 2:
1. Mt. Vesuvius eruption of 79 CE
2.
GEOLOGY TERMS/CONCEPTS FOR TEST 2:
1.(6)-ash: fine pyroclastic material less than 4 mm in diameter.
2. (6)-aa: Lava flow with a rough, blocky surface. Higher viscosity flow than
Pahoehoe lava. Both are Hawaiian terms.
3. (6)-caldera: A large (over 2 km in diameter) basin-shaped volcanic depression,
roughly circular in map view, that forms by a piston-like collapse of a cylinder of
overlying rock into an underlying, partially evacuated magma chamber.
4. (6)-cinder or scoria cone: a small cone or horseshoe-shaped hill made up of
pyroclastic debris (commonly scoria which is basaltic rocks with numerous holes
formed by gases escaping from magma.
5. (6)-composite volcano: A volcano constructed of alternating layers of
pyroclastic debris and lava flows. Also known as a stratovolcano.
6. (6)-crater: An abrupt basin commonly rimmed by ejected material. In
volcanoes, craters form by outward explosion, are commonly less than 2 km in
diameter, and occur at the summit of a volcanic cone. Similar rimmed basins
form by impacts with meteorites, asteroids and comets.
7. (6)-crystallization: The growth of minerals in a fluid such as magma.
8. (6)-decompression melting: The most common process creating magma;
achieved by reducing pressure on hot rock, not by adding more heat.
9. (6)-basalt: A dark-colored, finely crystalline VOLCANIC (cools fast at surface)
rock typical of low-viscosity oceanic lavas. Granite is a light-colored, coarsely
crystalline PLUTONIC (cools slow at depth) rock typical of the continental crust
from high viscosity magmas.
10. (6)-fissure: A narrow parting or crack in a rock.
11. (6)-flood basalt: Tremendous outpourings of basaltic lava that form thick,
extensive plateaus.
12. (6)-lahar: A volcanic mudflow composed of unconsolidated volcanic debris
and water.
13. (6)-lava dome: A mountain or hill made from highly viscous lava, which plugs
the central conduit of volcanoes.
14. (6)-mineral: A naturally formed, solid, inorganic material with a characteristic
chemical composition and physical properties that reflect an internally ordered
atomic structure.
15. (6)-obsidian: Dark volcanic glass.
16. (6)-pahoehoe: Lava flow with a smooth, ropy surface.
17. (6)-plutonic rock: Rock formed by the solidification of magma deep below the
surface. Named for Pluto, the Roman god of the underworld.
18. (6)-pumice: volcanic glass so full of holes that it commonly floats on water.
19. (6)-pyroclast and pyroclastic flow: magma and volcanic rock blasted up into
the air, a flow consists of high-temperature, fast-moving cloud of fine volcanic
debris, steam and other gases.
20. (6)-ridge (spreading center): a volcanic mountain range that lies along the
spreading centers on the floors of the oceans. Over 80% of Earth’s volcanism
takes places at the ridges (or spreading centers).
21. (6)-rock: a solid aggregate of minerals.
22. (6)-shield volcano: a very wide volcano built of low-viscosity lavas (commonly
basaltic lavas).
23. (6)-tetrahedron: one silicon and four oxygen atoms link up to form the siliconoxygen tetrahedron. This is one factor that influences the viscosity of
magma: the more tetrahedrons in the magma’s chemical makeup, the higher
the viscosity.
24. (6)-viscosity: the property of material that offers internal resistance to flow, its
internal friction. The lower the viscosity, the more fluid the behavior.
25. (6)-volcanic rock: rock formed by solidification of lava at the Earth’s surface.
(nothing for chapter 7)
24. (16)-comet: Icy body moving through outer space.
25. (16)-Kuiper belt: A flattened disk of comets with orbital periods of less than
200 years traveling in an orbital plane similar to the planets of the Solar System
but extending out 50 astronomical units.
26. (16)-asteroid: Stony or metallic mass that orbits the Sun.
27. (16)-maria: Dark, low-lying areas of the Moon filled with dark volcanic rocks.
28. (16)-meteor: A light phenomenon that occurs when a meteoroid enters Earth’s
atmosphere and vaporizes; commonly called a shooting star (tiny space
particles-about 1mm in diameter-that burn up with a flash of friction-generated
light in the Earth’s atmosphere); meteorite: A stony or metallic body from space
that passed through the atmosphere and landed on the surface of the Earth;
meteoroid: A general term for space objects made of metal, rock, dust or ice.
29. (16)-NEO: near-Earth object-A comet or asteroid whose orbit makes it
potentially hazardous to Earth.
30. (16)-Oort cloud: A vast and diffuse envelope of comets surrounding the Solar
System.
31. (16)-solar wind: The outflow of charged particles (ions) from the Sun.
32. (16)-tektite: Rounded pieces of silicate glass formed by impact melting.
33. (14)-backfire: A fire deliberately set to consume fuel in front of an advancing
wildfire in order to stop it.
34. (14)-combustion: Act of burning.
35. (14)-conduction: Transfer of heat downward or inward through material by
communication of kinetic energy from particle to particle.
36. (14)-diffusion: Intermingling movement caused by thermal agitation with flow
of particles from hotter to cooler zones.
37. (14)-fire: The rapid combination of oxygen with organic material to produce
flame, heat and light.
38. (14)-firestorm: A fire large enough to disturb the atmosphere with excess heat,
thus creating its own winds.
39. (14)-foehn winds: A warm, dry wind on the leeside of a mountain range.
Pronounced fewn.
40. (14)-fuel-driven fire: Fire burning on calm weather days that advances slowly
through the fuel, giving firefighters opportunities to stop the fire.
41. (14)-heat: The capacity to raise the temperature of a mass, expressed in
calories.
42. (14)-oxidation: Combination with oxygen. In fire, oxygen combines with
organic matter; in rust, oxygen combines with iron.
43. (14)-pyrolysis: Chemical decomposition by the action of heat.
44. (14)-radiation: Heat emitted as rays.
45. (14)-wind-driven fire: fire fronts that move fast. The wind carries firebrands
(e.g., embers) forward, starting spot fires several miles ahead. Firefighters
scramble to put out spot fires but can do little against the flame front.
TEST 2
PEOPLE FOR TEST 3: TBD
NATURAL DISASTER CASE HISTORIES FOR TEST 3: TBD
GEOLOGY TERMS/CONCEPTS FOR TEST 3:
1. (9)-climate: The average weather conditions at a place over many years. Based
mainly on temperature and precipitation data collected over decades.
2. (9)-Coriolis effect: Moving objects experience the Earth move out from beneath
them; in the Northern Hemisphere, bodies move toward their right-hand sides,
while in the Southern Hemisphere, they move toward their left.
3. (9)-cyclone: A region of low atmospheric pressure and converging air that
rotates counterclockwise in the Northern Hemisphere.
4. (9)-adiabatic process: The change in temperature of a mass without adding or
subtracting heat. Temperature change due to change in pressure. Examples are
cooling with expansion of air (decreased pressure) and warming upon
compression of air (increased pressure).
5. (9)-albedo: The reflectivity of a body: for the Earth, how much solar radiation is
reflected back to space.
6. (9)-anticyclone: A region of high atmospheric pressure and outflowing air that
rotates clockwise in the Northern Hemisphere.
7. (9)-dew point temperature: The air temperature when the relative humidity of an
air mass reaches 100% and excess water vapor condenses to liquid water.
8. (9)-front: A boundary separating air masses of different temperature or
moisture content.
9. (9)-greenhouse effect: The buildup of heat beneath substances such as glass,
water vapor, and carbon dioxide that allow incoming, short-wavelength solar
radiation to pass through, but block the return of long wavelength radiation.
10. (9)-heat capacity: The amount of heat required to raise the temperature of 1
gram of a substance by 1 degrees C.
11. (9)-humidity: The measure of the amount of water vapor in an air mass.
12. (9)-isobar: A map line connecting points of equal pressure.
13. (9)-lapse rate: The rate at which Earth’s atmosphere cools with increasing
altitude, or warms with decreasing altitude.
14. (9)-latent heat: The energy absorbed or released during a change of state.
15. (9)-lifting condensation level: The altitude in the atmosphere where rising air
cools to saturation (100% humidity) and condensation begins.
16. (9)-monsoon: Winds that reverse direction seasonally. In summer, warm air
rises above hot land, drawing in rain-bearing winds from over the ocean. In
winter, the flow reverses.
17. (9)-pressure gradient: Perpendicular to the air pressure isobars on a map is a
gradient or slope of pressure change. Air flows from high to low pressure.
18. (9)-solar radiation: Energy emitted from the Sun, mostly in the infrared, visible
light and ultraviolet wavelengths.
19. (9)-stratosphere: The stable atmospheric layer above the troposphere.
20. (9)-thermohaline flow: The flow of deep ocean waters made denser by
coldness (thermo) and saltiness (haline).
21. (9)-troposphere: The lowest layer of the atmosphere, ranging from 18 km (11
mi) thick at the equator to 8 km (5 mi) thick at the poles.
22. (10)-air-mass thuderstorm: Local, short-lived thunderstorm that may form and
dissipate in several hours. Common type in Imperial Valley.
23. (10)-cumulus: A tall, thick cloud made of rounded masses stacked upon each
other, all above a horizontal base.
24. (10)-derecho: Winds that blow straight ahead.
25. (10)-downburst: A localized, severe downdraft of air that includes an outburst
of strong winds on the ground.
26. (10)-freezing rain: Supercooled rain that turns to ice when it touches objects
such as trees and powerlines.
27. (10)-hypothermia and hyperthermia: HYPO: Overheating of the body
commonly due to extreme weather. Body temperatures greater than 40 degrees C
(104 degrees F) can be life threatening; HYPER: Occurs when body temperature
drops below 35 degrees C (95 degrees F) and the heart, respiratory and other
systems cannot function normally.
28. (10)-lake-effect snow: Snow produced after cold air blows over large areas of
warmer water, picking up water vapor that forms clouds that precipitate snow just
past the downwind shoreline.
29. (10)-lightning: A flashing of light as atmospheric electricity flows between
clouds or between clouds and the ground.
30. (10)-mesocyclone: A rotating mid-level region within a supercell
thunderstorm.
31. (10)-nor’easter: A winter weather condition involving a low-pressure system
with its center offshore of the Atlantic coasts of the US and Canada. The
counterclockwise rotation brings warm moist offshore air into contrast with cold
Arctic air.
32. (10)-severe thunderstorm: Thunderstorm with winds greater than 58 mph; it
can produce large hail and tornadoes.
33. (10)-supercell thunderstorm: A complex thunderstorm formed from a huge
updraft. They commonly are tilted, allowing rain, hail and tornadoes to exist sideby-side.
34. (10)-thunder: The sound given off by rapidly expanding gases along the path
of a lightning discharge.
35. (10)-thunderstorm: A tall, buoyant cloud of moist air that generates lightning
and thunder, usually accompanied by rain, gusty winds and sometimes hail.
36. (10)-tornadoes and tornado outbreak: Spinning funnels of wind whose
rotating wind speeds can exceed 300 mph. An outbreak occurs when six or more
tornadoes occur within a 24 hour period from a single weather system.
37. (11)-eye and eyewall: Forms in the center of a hurricane when winds speeds
exceed 119 km/hr (74 mph). Descending air in the eye warms, causing clear air.
The eyewall surrounds the eye where winds spiral upward. Winds speed and
precipitation are greatest here.
38. (11)-hurricane: A large, tropical cyclonic storm with wind speeds exceeding
119 km/hr (74 mph); called a typhoon in the western Pacific Ocean and a cyclone
in the Indian Ocean.
39. (11)-surge: A large amount of seawater that build up within the eye of the
hurricane and then spills onto land.
40. (12)-El Nino: A climate pattern that occurs every 2-7 years when the trade
winds relax and warm ocean water in the equatorial Pacific Ocean flows to the
west coast of North America.
41. (12)-extinction: The die-off or elimination of a species.
42. (12)-La Nina: A climate pattern that occurs when cooler than normal seawater
exists in the tropical eastern Pacific Ocean.
43. (12)-Little Ice Age: A colder interval between about 1400 and 1900 CE marked
by renewed glaciation in the Northern Hemisphere.
44. (12)-methane: A gaseous hydrocarbon (CH4).
45. (12)-Milankovitch theory: Glacial advances and retreats on Earth are
controlled by variations in the amount of solar radiation received at high latitudes
during summer due to changes in the Earth’s orbit around the Sun and in the tilt
angle and direction of Earth’s axis of rotation.
46. (12)-ozone: A gaseous molecule composed of three atoms of oxygen. The
ozone layer that protects us from harmful UV radiation is produced in the
stratosphere.
47. (12)-sunspot: A dark area on the Sun’s surface with below-average
temperature.
48. (12)-tipping point: The point at which long-term small changes suddenly
produce large effects.
Test 3